Study: Drink Water Only When Thirsty!

tumblr_lyjbxs1KGq1qeucjro5_250In years past, we’ve been advised to drink water before we’re thirsty during exercise. By the time you’re thirsty, they said, you’re already dehydrated. And that still may be true. But researchers are finding that our bodies are actually well equipped to deal with some dehydration during physical activity. Moreover, they’ve found that more water may not be a good thing.

During physical activity, our bodies sweat to release excess heat. It’s like a built-in air conditioning system. However, when we don’t replace the fluids lost by sweat, dehydration occurs. As a result, your body may not have enough fluids to carry out its normal functions.

But a slew of recent studies are showing that some dehydration does not necessarily have a negative impact on performance or on overall health. In fact, it may be a good thing.

Case in point, a study by researchers at the Sports Science Institute of South Africa. They broke exercisers into three groups. The first group drank by thirst, the second group hydrated at moderate rate and the third group hydrated at a heavy rate. After completing three, 2-hour workouts, researchers found that there was no difference in body temperature or finishing times among the groups. The did find, however, that some individuals in the heavily hydrated group experienced stomach pains and couldn’t complete the workout.

In another study of marathon runners in France, researchers found that the fastest runners (who completed the course in under three hours) had lost 3.1% of their body weight through sweat and/or urine. They were faster – and significantly more dehydrated than – their slower counterparts.

In yet another study, researchers from University of Sherbrooke in Quebec analyzed various clinical trials. They discovered that mild hydration is perfectly safe – and that it can actually provide a boost to performance. After examining different groups of cyclists, those who only drank when they were thirsty had the best times.

But why? Researchers speculate that drinking too much water can dilute the concentration of sodium and other electrolytes in the blood. This is especially pronounced during longer periods of physical exercise.

The important thing to remember is that when it comes to hydration during exercise, listen to your body. If you’re thirsty, drink.


About Davey Wavey

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  1. Taylor Dean Whitcomb says:

    Hey Davey,

    I was wondering if you might be able to help me find the sources that you used (and/or the peer-review articles) for this study, I really wanted to read the scientific literature here, but I am having trouble finding them myself! I appreciate your help!

    Taylor Dean

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